Third-grader Harry thinks of a way to patch up a conflict with his schoolmate Mary and include his friends in a fun detective case with rewards for everyone, including Grandpa.
When the origami pig that Song Lee made for her grandmother is seized by a substitute teacher, the usually well-behaved third-grader breaks a classroom rule to rescue it from the June box.
Mary decides it's all right to cheat to make sure she wins a special lunch with her favorite teacher, but the results of her dishonesty end up surprising the whole second grade class.
Four stories featuring the school activities of second-graders Harry and Doug as they participate in a secret mission to celebrate "Charlotte's Web," learn how to make green slime, and put on a skit warning about the dangers of smoking.
When his best friend Doug discovers his top-secret hideout, Harry enlists his friends' help to save it from being developed into an apartment building.